This invention relates generally to medicinal capsule making machines and specifically to a capsule making machine employing improved pin bars and air flow characteristics.
It is well known to provide a gelatin, hard shell capsule making machine employing pin bars which sequentially move from a preheating station, to a greasing station, dipping/spinning/front elevator station, upper deck heating kiln, rear elevator, lower deck heating kiln, and finally to an automatics section. One such device is disclosed within U.S. Pat. No. 1,787,777 entitled "Capsule Machine" which issued to Colton on Jan. 6, 1931, and is incorporated by reference herewithin.
Most conventional capsule making machines employ pin bars consisting of an elongated base and a plurality of depending pins. The pins are dipped into a liquid gelatin capsule solution at the dipping station. The gelatin capsule solution adheres to the pins and is subsequently dried and hardened within a heated kiln. The hardened capsules are then cut and removed within the automatics station. Thereafter, the automatics station temporarily joins the cap portion of the capsule with the body portion of the capsule. Cellulose capsule making machines are somewhat similar to the gelatin capsule making machines except that cooled pin bars are placed within a relatively hot gelatin capsule solution and then subsequently hardened by cooling in cooling chambers in place of the kilns.
Conventional pin bars have a rectangular cross sectional shape. The pins are typically inserted into a set of openings centrally located within the otherwise solid and unpierced base. This set of openings are longitudinally aligned and adapted to receive a constricted portion of the pins. Such exemplary pins and pin bars are disclosed within U.S. Pat. Nos.: 4,758,149 entitled "Capsule Forming Pin Having a Burnish-Hardened Surface" which issued to Sauter on Jul. 19, 1988; 5,032,074 entitled "Apparatus for Manufacturing Hard Capsules for Medicament Use" which issued to Muto et al. on Jul. 16, 1991; 4,997,359 entitled "Multi-Well Dish for Capsule Making" which issued to Lebrun on Mar. 5, 1991; 4,627,808 entitled "Apparatus for Making Capsule having Plural Chambers" which issued to Hughes on Dec. 9, 1986; and 3,399,803 entitled "Self-Locking Medicament Capsule" which issued to Oglevee et al. on Sep. 3, 1968. The preceding patents are all incorporated by reference herewithin. Solid pin bars are also disclosed within WIPO Patent Publication No. WO 92/21311 entitled "Method and Apparatus for the Manufacture of Pharmaceutical Cellulose Capsules", published on Dec. 10, 1992, and Canadian Patent No. 1 151 823 entitled "Hard Shell Gelatin Capsule Dipping Apparatus and Method" which issued on Aug. 16, 1983.
These traditional solid pin bars retard desired air flow within the drying kilns since hundreds of these pin bars are closely juxtapositioned within the upper deck kiln and the lower deck kiln. Therefore, essentially no heated air can pass through the bases of the pin bars and extremely little heated air can pass between the tightly packed bases. This is schematically shown in FIG. 1 which illustrates one side of a traditional machine. In this figure, heated air is blown from a hood 21 and directed downward upon the upstanding pins 23. This air stream is then deflected to the side of the kiln by the bases of the pin bars such that the air flow is then received by an outlet 25 alongside the kiln. Thus, these solid pin bars do not allow for uniform air flow to the innermost rows of the pins thereby allowing undesired irregularities in the final capsule wall thickness and the like. This leads to inefficient heating, costly scrappage of parts and a less than optimum process control.
A variety of drying duct formations have also been employed with traditional capsule making machines. For example, reference should be made to U.S. Pat. Nos. 1,978,829 entitled "Method and Apparatus for Drying Capsules" which issued to Wilkie on Oct. 30, 1934 and 1,114,325 entitled "Capsule Machine" which issued to Winchester on Oct. 20, 1914. These conventional ducts are often cumbersome and difficult to package within modern capsule making machines. Accordingly, it would be desirable to provide improved pin bars which enhance uniform air flow and heating characteristics. It would also be desirable to employ more easily packaged hoods.